Single button (like the disable/enable popups) to stop and start downloads with captchas would be very very cool.
If you are going to be away from computer for a while, stopping all captchas, while allowing premium and non-capcha downloads to continue...
Having to manually disable selectively is a real PITA, and if you don't disable the V3 recaptcha "automated request" flag goes up.

Either you can change Settings-Advanced Settings-CaptchaSettings.captchamode to SKIP_ALL
and JDownloader will automatically skip all Captchas.
Or you enable the bottom in top menu bar 'Silent Mode' that will also prevent Captcha/Dialogs to popup.
Also check Settings-Advanced Settings-SilentModeSettings.oncaptchaduringsilentmodeaction